Estimation and Story Points

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Estimation

Estimation

  • Helps make decisions
  • Priority/sequencing of work
  • Splitting/merging user stories
  • How much can we do?
  • Helps to build trust

Warning:

  • Not only law of diminishing returns
  • More might actually be less

Quick exercise

  • What do you think is the relationship between time spent estimating and accuracy?

Group Exercise – Estimation

In your groups…

  • How have you estimated work in the past?
  • What is the relationship between work load and deadlines?
  • Scope, Resources, Deadline, Quality…
    • Which of these do you explicitly decide upon
    • Which do you leave hanging?
    • Who chooses each of these? Customers, users, developers, ???

Class Exercise – Estimation Observations

Report back from your group meeting

Individual Exercise – Estimation

Note, this example comes from Cohn’s “User Stories Applied”

Individually…

  • From 1 to 10, estimate each based on average height at their shoulders:
    • Labrador Retriever
    • Vizsla
    • Terrier
    • Great Dane
    • Standard Poodle
    • French Bulldog
    • Dachshund
    • German Short-haired Pointer

Group Exercise – Estimation

In our groups of 4…

  • From 1 to 10, estimate each based on average height at their shoulders:
    • Labrador Retriever
    • Vizsla
    • Terrier
    • Great Dane
    • Standard Poodle
    • French Bulldog
    • Dachshund
    • German Short-haired Pointer

  • Be prepared to discuss the difference in the two experiences

Class Exercise – Compare Individual/Group

Discuss your differences between the individual exercise and the group exercise

Story Points

Story points

  • Are relative
  • Are arbitrary units of measure
  • Each team defines how they see fit
  • Combine complexity, size, risk, etc.

Who?

  • The whole team
  • Users/customers provide input, answer questions
  • Developers make the call

NOTE!

  • Estimates are the exclusive purview of developers
  • No manager/product owner bullying.

Approaches (Must Haves Only)

Planning Poker

  • Someone reads user story
  • Product owner answers any questions
  • Everybody selects an estimate from a collection of cards
  • Everybody shows their estimate
  • If “wide” variation, group discussion (with time box)
  • Repeat until “near” convergence
  • To organize this,
  • Have decks of prepared cards (playing cards, 3x5 cards)
  • One deck per person estimating (developers)
  • Each deck has same set of numbers,
    • 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
    • 1, 2, 3, 7, 10, 17, 27

Group Exercise – Estimates

In your groups…
  • Remember to make your meeting work
  • Use planning poker on a few cards
  • Notes
  • Really, it is only developers who estimate
  • Product owners, users, managers do not estimate
  • Be prepared to discuss your answers
    • Ah-ha’s
    • Oh’s

Class Exercise – Estimates

What are the challenges at your organization to this style of estimation?